<template>
  <div class="hello">
    <h1>{{ msg }}</h1>
    <h2>Essential Links</h2>
    <ul>
      <li>
        <a
          href="https://vuejs.org"
          target="_blank"
        >
          Core Docs
        </a>
      </li>
      <li>
        <a
          href="https://forum.vuejs.org"
          target="_blank"
        >
          Forum
        </a>
      </li>
      <li>
        <a
          href="https://chat.vuejs.org"
          target="_blank"
        >
          Community Chat
        </a>
      </li>
      <li>
        <a
          href="https://twitter.com/vuejs"
          target="_blank"
        >
          Twitter
        </a>
      </li>
      <br>
      <li>
        <a
          href="http://vuejs-templates.github.io/webpack/"
          target="_blank"
        >
          Docs for This Template
        </a>
      </li>
    </ul>
    <h2>Ecosystem</h2>
    <ul>
      <li>
        <a
          href="http://router.vuejs.org/"
          target="_blank"
        >
          vue-router
        </a>
      </li>
      <li>
        <a
          href="http://vuex.vuejs.org/"
          target="_blank"
        >
          vuex
        </a>
      </li>
      <li>
        <a
          href="http://vue-loader.vuejs.org/"
          target="_blank"
        >
          vue-loader
        </a>
      </li>
      <li>
        <a
          href="https://github.com/vuejs/awesome-vue"
          target="_blank"
        >
          awesome-vue
        </a>
      </li>
    </ul>
    <div>
    <div>
    <select v-model="select1">
      <option v-for="x of 10" :key="x" v-if="x == select1 || !selected.includes(x.toString())">{{x}}</option>
    </select>
    <select v-model="select2">
      <option v-for="x of 10" :key="x" v-if="x == select2 || !selected.includes(x.toString())">{{x}}</option>
    </select>
    <select v-model="select3">
      <option v-for="x of 10" :key="x" v-if="x == select3 || !selected.includes(x.toString())">{{x}}</option>
    </select>
  </div>
  </div>
  </div>
</template>

<script>
export default {
  name: 'HelloWorld',
  data () {
    return {
      msg: 'Welcome to Your Vue.js App',
      parArr: [],
      selectIdsArr: [],
       select1: undefined,
      select2: undefined,
      select3: undefined,
      programList: [
        {
          id: 1,
          name: "选项1"
        },
        {
          id: 2,
          name: "选项2"
        },
        {
          id: 3,
          name: "选项3"
        }
      ]
    }
  },
  computed: {
    selected () {
      return [this.select1, this.select2, this.select3]
    }
  },
  methods: {
    onChangeProgram() {
      this.selectIdsArr = [];
      for (const item of this.parArr) {
        if (item.id) {
          this.selectIdsArr.push(item.id);
        }
      }
    }
  }
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
h1, h2 {
  font-weight: normal;
}
ul {
  list-style-type: none;
  padding: 0;
}
li {
  display: inline-block;
  margin: 0 10px;
}
a {
  color: #42b983;
}
</style>
